package symbol;
import java.util.*;
import lexer.*;
import inter.*;

public class Env {
    private Hashtable table;
    protected Env prev;
    public Env(Env n){
        table = new Hashtable();
        prev = n;
    }

    public void put(Token w, Id i){
        table.put(w, i);
    }

    public Id get(Token w){
        for(Env e = this; e != null; e = e.prev){
            Id found = (Id)(e.table.get(w));
            if(found != null) return found;
        }

        return null;
    }
}